Tiltable crucible or converter for refining pig iron



o. PUHRINGER 3,502,314

TILTABLE CRUCIBLE OR CONVERTER FOR REFINING PIG IRON March 24, 1970 5Sheets-Sheet 1 Filed Nov. 50, 1967 [NVENTOR OTH MAR PUH RINGER HISATTORNEYS March 24, 1970 o. PUHRINGER 5 3 TILTABLE CRUCIBLE OR CONVERTERFOR REFINING PIG IRON 3 Sheets-Sheet 2 Filed Nov. 30, 1967 x 2 a W :mx Jf/ V. ll 4 M 9) r 8\ %mungu c k mm 3 .u a I & m 3 V. l'l.

[NVENTOR OTHMAR PUHRINGER HIS AT TORNEYS March 24, 1970 QPUHRINGER 5 3TILTABLE CRUCIBLE OR CONVERTER FOR REFINING PIG IRON Filed Nov. 30, 19573 Sheets-Sheet 3 [NVENTOR OTAAR PUHRINGER HIS ATTORNEYS United StatesPatent O U.S. Cl. 266-36 7 Claims ABSTRACT OF THE DISCLOSURE A tiltableconverter for metallurgical processes is supported from an annularcarrying ring by a plurality of brackets, each of which employs aninclined plane bearing surface to allow for thermal expansion. Thebearing surfaces are formed between fixed wedges secured to fiangesprojecting radially from the converter and respective adjustable wedgesmounted on both the top and bottom of the carrying ring. The preferredinclination of the bearing surface (to a plane normal to the converteraXis) is substantially equal to the ratio of the distance parallel tothe longitudinal axis of the converter between opposed bearing surfaceson top and bottom of the carrying ring, divided by four times the radialdistance of a fixed wedge from the longitudinal axis.

Two pairs of upper and lower carrying flanges and one pair of tiltingflanges are provided, the former above and below the respectiveconverter trunnions and the latter mdway between the trunnions. Bothseparate flange segments at each support location and continuous fiangesabout the converter periphery are disclosed.

The invention relates to a tiltable crucible or converter for refiningpig iron, which is supported in an annular carrying ring surrounding theshell of the crucible by means of supporting elements, such as pairs ofbrackets, -Which take up the bearing stresses. The carrying ring isrigidly connected to two trunnions placed on diametrically oppositesides. The crucible must be tiltable from the substantially verticalblowing position into the upsidedown position for complete dischargingand back into the upright position 'by means of electric or hydraulicdrives actng on the trunnions.

An important problem in the Construction of crucible or converterassemblies resides in the provision that the high temperatures, -whichthe crucible shell reaches during operation, do not have any detrimentaleflect upon the Construction. In particular, provision has to be madethat thermal expansions of the crucible shell and the difference inexpansion between crucible shell and refractory lining cannot displacethe diametrically opposite trunnions from their coaxial alignment.Furthermore, provision has to be made that n-o dangerous Shock stresseson the converter mounting can be caused as a result of developingclearances.

Various ways of fulfilling this demand have been tried. For instance,converters without carrying rings were built, where the trunnions aremounted directly to the shell by means of joining elements. Althoughwith this construction any clearance in the converter mounting cannotoccur, the stresses resulting from thermal expansion cannot easily beaccommodated and the inevitable deformations of the vessel find animmediate response in a misalignment of the trunnions. It has also beensuggested to build a converter -with a welded-in carrying ring, thecarrying ring being designed as reinforced middle part ot the converterand the trunnions being mounted directly ice on the carrying middlepart. With this Construction it is also difiicult to securelyaccommodate the stresses resulting from thermal expansons or from thedifference in thermal expansion between refractory lining and carryingshell.

The most robust Construction so far known remains yet a crucible orconverter Suspended in a separate structural part, i.e. the carryingring, which surrounds the shell of the crucible in spaced relatonship,approximately in the height of its center of gravity, and the presentinvention relates to that kind of a crucible or converter assembly.

With known types of this kind of converter construction, the supportingmeans taking up the bearing stresses were usually designed as pairs ofbrackets spaced around the periphery of the crucible shell and engagngthe carrying ring by means of a projecting fiange. In the uprightposition of the crucible, the bearing surfaces define a horizontalplane. When the shell of the crucible reaches a higher temperatureduring operation, thermal expansion causes a clearance at the unstressedbearing surfaces, because the crucible 'with the brackets mountedthereon expands more than the carrying ring. This causes heavy impactshocks when the crucible is tilted, as the crucible rocks to and frobetween upper and lower brackets. The Shock stress resulting from theexpansion clearance is extremely detrimental to the whole Construction,especially for the bearings, and it reaches inadmissibly high valueswith large converters having an output capacity of to 300 metric tons.

To avoid this disadvantage, it has already been suggested to design thebearing surfaces of the lower supporting lugs as inclined planesslanting towards the center of the ring, the inclination correspondingto an angle a, which is defined by the ratio of the distance betweenupper and lower bearing surfaces divided by the radius of the vessel.This angle oc corresponds to the proportion of axial to radial expansonand would theoretically enable a clearance-free expansion on the lowerbrackets. In practice, however, such conditions cannot be attained dueto the fact that the degree of heating of the crucible surface variesduring a crucible campaign. In addition, other deformations anddistortions occur apart from the theoretical longitudinal and radialexpansion. Practice has shown that stresses having their origin in thefabrication (lamination, weldng) come into effcct during heating of thecrucible shell and the carrying ring, which stresses urge forcompensation and thereby cause deformations. A consequence thereof arepermanent deformations. These deformations do not recede even if thetemperature is equalized. For these reasons, the design with aninclination angle x on the lower supporting lugs does not result in thedesired clearance-free expansion, but a dangerous jamming occurs, whichleads to incalculable increases in the stress on the crucible wall andthe carrying ring.

According to U.S. Patent No. 3,337,205, which is based on a similartrain of thought, it has been suggested to divide up the theoreticalthermal expansion angle oc upon upper and lower brackets so that thebearing surfaces in that Construction are designed with only half theinclination, i.e. oc/ 2. The danger of jamming is already diminished inthat Construction.

The present invention relates to a further development and improvementof a crucible mounting having bearing surfaces inclined towards thecenter of the ring, and has as its object to safeguard a reliableconverter suspension even with extreme differences in the temperaturedistribution. In certain top-blowing processes, such as the LDACprocess, the top part of the converter is, as a whole, considerablywarmer than the bottom part of the converter. There are also cases wherethe temperature distribution is reversed, e.g. towards the end of acrucible campaign, when the lining in the bath area is more stronglyworn. The bottom part of the converter in the range of the lowerbrackets then is considerably warmer than the top part. Local radialexpansions in the range of the upper and lower brackets, which arelarger than the axial expansion, may result from these great differencesin temperature. Accordingly, an angle a or even x/Z for the inclinationof the bearing surfaces would not be suited for actual Operatingconditions. Jammings between brackets and carrying ring may occur,imparting uncontrollable stresses to the whole joining structure.

A further object of the invention resides in that a secure suspensionand support of the crucible has to be guaranteed even in the horizontaltilted position. With known constructions it has often happened thatshock stresses have resulted from a side clearance developing betweenthe supporting lugs and a stop on the carrying ring.

The construction of the invention, which solves these problems, ischaracterised according to its main feature in that the inclination ofthe bearing surfaces is smaller than the ratio H /D, preferably H /2D,wheren H stands for the aXial distance between upper and lower bearingsurfaces and D stands for twice the radial distance of the bearingsurfaces from the longitudinal axis of the crucible. According to thepreferred embodiment, the inclination of the bearing surfaces thuscorresponds to an angle of oc/4. These inclined bearing surfaces areprovided on the upper as well as on the lower supporting means.

The inclined bearing surfaces are suitably provided on supporting meansarranged in pairs, so-called pairs of brackets, of which two pairs ofbrackets, the supporting bracket pairs, are arranged diametricallyopposite substantially in the trunnion axis, and a further pair of abrackets, the tilting bracket pair, is substantially perpendicular tothe trunnion axis. According to a modified embodiment of the invention,the inclined bearing surfaces may also be spaeed around a ring-shapedsupporting construction surrounding the crucible shell and being fixedthereto, said supporting construction comprising an upper belt, a lowerbelt, and ribs mounted between these belts, and having disconnectingrecesses, if desired.

According to a preferred characteristic of the invention, the inclinedbearing surfaces are detachable and adjustable. They may be provided ona pair of wedges, one of said wedges being rigidly welded to theprojecting flange of a supporting element or releasably connectedtherewith by means of a shearing bolt, and the other of said wedgesbeing releasably and adjustably connected with a guide means of thecarrying ring. The guide means of the carrying ring comprises a lateralguidance and a radial guidance, the lateral guidance being formed byrails mounted on the carrying ring by means of screws, and the radialguidance comprising a centering shoe which abuts on the carrying ringand has a fixing screw which reaches into the wedge and penetratesfitting plates.

A special characteristic of the invention, which secures the horizontaltilt position of the crucible, resides in the inclined bearing surfacesof each supporting bracket being designed as two pairs of wedgesarranged symmetrical of the trunnion aXis, a stopping block beingprovided between them in a conical recess on the carrying ring, saidstopping block being adapted to be centered in relation to the walls ofthe conical recess of the carrying ring by means of side wedges withfitting plates and fixing screws.

The construction according to the invention combines the advantages ofthe known constructions without having their disadvantages. The dangerof jammings is excluded, while the clearance resulting from the thermal.

expansion keeps within acceptable limits, i.e. sudden shock stressesduring tilting are avoided. The weight of the charged crucible orconverter is carried by the main supporting brackets in the range of thetrunnions, when the crucible is in the erect position. The stress causedby the tilting moment during turning of the crucible is accommodated bythe tilting bracket. The theoretical calculation for the bearing of thecrucible may thus be based on a three-point support, each of the threepoints being, for constructional reasons, spread over two adjacentbearing surfaces, which has an advantageous eflect upon thetheoretically calculated stresses.

Embodiments of the invention are illustrated in the drawing. FIG. 1shows a crucible with carrying ring and supporting means in elevationand partly in cross-section. FIG. 2 shows the ground-plan of FIG. 1.FIG. 3 shows a vertical cross-section through a supporting bracket alongthe line III- III of FIG. 2 on an enlarged scale, FIG. 4 a cross-sectionalong the line lV-IV of FIG. 3, and FIG. 5 is the ground-plan of FIG. 4along the sectional line V-V of FIG. 4. FIG. 6 shows a cross-sectionalong the line VI-VI of FIG. 1 and demonstrates the mounting of theadjusting wedges for the stopping blocks for accommodating the crucibleweight in the horizontal position of the crucible. FIGS. 7 and 8 showelevation and groundplan of a modified embodiment.

Numeral 1 in the drawings denotes the crucible, having a refractorylining 2. A carrying ring 10 surrounds the shell of the crucible; it mayconsst of several parts, as shown in FIG. 2. The crucible 1 is Suspendedin the carrying ring by means of pairs of brackets, pairs of brackets 4,4', and 3, 3' being arranged substantially in the trunnion axis andacting as supporting brackets, while the pair of tilting brackets 5, 5'is arranged perpendicular thereto. These three pairs of brackets are ofidentical design. For constructional reasons, they are designed as pairsof double-brackets. A guide means 6 is arranged diametrically oppositeof the pair of tilting brackets, and is designed in known manner foraccommodating lateral stresses, but does not abut the carrying ring.

As shown in FIG. 3, each bracket 3, 3', 4, 4', 5, 5' comprises an upperbelt 3a welded to the crucible shell 1, a lower belt 3b welded to thecrucible shell, and intermediate ribs 3c welded to the converter shell.Alternatively, a common screw-type connection between brackets andvessel is also possible. A wedge-shaped bearing plate 8 is detachablyconnected to the lower belt 3b by means of a shearing bolt 7, said plateresting upon a corresponding wedge-shaped counter piece 9 detachablyconnected to the carrying ring 10. The bearing surfaces of the wedgeplate 8 and the counter piece 9 are inclined towards the center of thering, their inclination being defined by H/2D (FIG. 1), corresponding toan angle of oc/4 according to the previously given definition. Thedetachable mounting of the counter piece 9 is effected by means of acentering shoe 11 having a nose 11a. Fitting plates 12 are inserted intothe gap between nose 11a and counter piece 9. Fixing screws 13 penetratethrough bores of the nose part 11a and of the fitting plates 12 into thecounter piece 9 and hold it fast against the nose lla.

Rails 14 and 15 are mounted on the carrying ring 10 for lateral guidanceof the wedge portion 9 on the carrying ring (FIG. 4), rail 15 beingreplaceable, so that wedge portion 9 may be laterally dismounted. Rail15 is fixed to the carrying ring by screws 16.

The mounting support of the crucible for the horizontal tilt position isshown in FIGS. l and 6. The crucible weight is carried by stoppingblocks 17, arranged on the supporting brackets between two wedgeportions 8 and lying in a recess of the carrying ring, which recess isformed by carrying ring noses 19. As shown in FIG. 6, the recess tapersradially outwardly, i.e. it is conical. Side wedges 18 are laid againstthe walls of the carrying ring noses 19 on both sides of the stoppingblock 17, a slight play being adjusted between said wedges and thecarrying ring noses 19. Ftting plates 20, inserted between a bridge 21fixed to the noses 19 and the wedges 18, are provided for adjustingwedges 18. The wedges are held against bridge 21 by means of screws 22.

According to the modified embodiment shown in FIGS.

7 and 8, a continuous supporting bracket ring is provided forreinforcing the whole vessel, said ring comprising an upper belt 23a, alower belt 23b, and intermediate ribs 23c. The belts and ribs are weldedto the crucible shell, disconnecting recesses 23d being provided on thering, which serve to prevent excessive stresses due to a temperaturegradent in the annular belts. In those zones of the crucible shell,which, owing to the relieve apertures, are non-engaged, any excessivestresses which may occur can be reduced by allowing a local flow in thecrucible shell. Apart from that, the design of the inclined bearingsurfaces as pairs of wedges and also the horizontal support constructionare the same as described in connection With FIGS. 1 to 6.

What I claim is:

1. In a tiltable steelmaking converter:

a vessel, substantially circular in cross-section;

a peripheral annular ring having upper and lower walls spaced radiallyfrom said vessel;

a number of upper and lower brackets on said vessel having radiallyprojecting flanges extending substantially parallel to said upper andlower walls of said rng;

each flange having at least one fixed wedge secured thereto with aninclined bearing surface facing said annular ring;

a number of complementary adjustable wedges releasably mounted on saidupper and lower walls of said ring and having inclined bearing surfacesfor engagement With respective bearing surfaces of said fixed wedges;

said fixed and adjustable wedges having engagng bearing surfacesextending at an angle having an inclination substantially equal to theratio of the axial distance separating the facing bearing surfaces on apair of fixed wedges Secured, respectively, to an' upper and a lowerbracket, divided by four times the radial distance of a fixed wedge fromthe longitudinal axis of said vessel.

2. In a tiltable steelmaking converter:

a vessel, substantially circular in cross-section;

a peripheral annular ring spaced radially from said vessel and havingupper and lower walls;

a pair of trunnions having a common aXis and extending in oppositedirections from said annular ring;

two pars of upper and lower carrying brackets on said vessel havingradially projecting flanges extending substantially parallel to saidupper and lower walls of said ring in the direction of said aXis of saidtrunnions;

a pair of upper and lower tilting brackets having flanges extendngsubstantially parallel to said upper and lower walls of said ring in adirection perpendicular to said axis of said trunnions;

each fiange of said carrying and tilting brackets having at least onefixed wedge Secured thereto with an inclined bearing surface facing saidannular ring;

a number of complementary adjustable wedges releasably mounted on saidupper and lower walls of said ring and having inclined bearing surfacesfor engagement with respective bearing surfaces of said fixed wedges;

said fixed and adjustable wedges having their engagng bearing surfacesextending at an angle having an inclination substantially equal to theratio of the aXial distance separating the facing bearing surfaoes on apair of fixed wedges Secured to respective ones of a pair of upper andlower brackets, divided by four times the radial distance of a fixedwedge from the longitudinal axis of said vessel.

3. In a steelmaking converter as recited in claim 2:

a number of guide means on said upper and lower walls of said annularring for mounting a respective one of said adjustable wedges;

each guide means comprising a pair of rails screwmounted on said ringfor lateral guidance of an adjustable wedge, and a centering shoesupported on said ring and holding a fixing screw extending into saidadjustable wedge, for radial guidance of said wedge.

4. In a steelmaking converter as recited in claim 2:

two fixed wedges on each flange of each pair of carrying brackets,arranged symmetrically of said trunnion axis and engagng withcorrespondingly arranged adjustable wedges on said annular ring;

a stopping block mounted on each of said flanges between said two fixedwedges thereof;

said stopping block being inserted in a conical recess of said annularring and adapted to be centered in relation to said conical recess bymeans of lateral keys bridged by a connecting member Secured to saidkeys by fixing screws having fitting plates thereon.

5. In a steelnaking converter as recited in claim 2:

a shearing bolt mounting each fixed wedge on a projecting bracketflange.

6. In a tiltable steelmaking converter:

a vessel, substantially circular in cross-section;

a peripheral ring having upper and lower walls spaced radially from saidvessel;

an upper and a lower annular supporting construction rigdly secured toand surrounding said vessel;

each supporting construction comprising a first belt, a second beltextending adjacent to and substantially in parallel with said upper andlower walls of said ring, and a plurality of ribs connecting said belts;

a number of spaced-apart fixed wedges Secured to each second belt, eachof said fixed wedges having an inclined bearing surface facing saidperipheral ring;

a number of complementary adjustable wedges releasably mounted on saidupper and lower walls of said ring and having inclined bearing surfacesfor engagement with respective bearing surfaces of said fixed wedges;

said fixed and adjustable wedges having their engagng bearing surfacesextending at an angle having an inclnation substantially equal to theratio of the distance separating the engagng bearing surfaces of a pairof axially aligned fixed wedges on respective ones of said second belts,divided by four times the radial distance of a fixed wedge from thelongitudinal aXis of said vessel;

said adjustable wedges being mounted on said ring by means of lateraland radial guide members.

7. In a steelrnaking converter as recited in claim 6:

disconnecting recesses on said first and second belts of said supportingconstructions adjacent to said vessel.

References Cited UNITED STATES PATENTS 3,l63,696 12/1964 Johansson et al266-36 3,372,205 8/1967 Puxkandl 266--36 J. SPENCER OVERI-IOLSER,Primary Examiner J. S. BROWN, Assistant Examiner g g UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,5 ,3 Dated March 9Inventor(3) Othmar P'ihringer It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Col. 1, line l, "Vereingte" should read --Vereinigte--;

Col. 6, line 64, "3,372,2o5" should read --3,337,2o5--.

SIGNED AND SEALED JUL 41970 Amet:

a M. Fle-wher. Iu I in Office: IIAM E. MHUYLER, JR.

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